We'd be delighted to assist you in changing the Master Admin from your QuickBooks Desktop (QBDT) company, Platterell1. 

To help you change the primary admin, you can sign in to Intuit Account User Management from a web browser, or you could also follow the steps I've provided below:

1. In your QBDT account, go to the Company menu and click Users.
2. Select Intuit Accountant Users Management.
3. Choose the company file you'd like to transfer and select Continue.
4. From the Users tab, select the current primary admin and click Change primary admin.
5. Click on the dropdown icon and choose the desired user to transfer the primary admin role.
6. Tap Verify.
7. Sign in using your Intuit account information and confirm the invite by selecting OK.

Once the invite is received, let's ensure to accept them by the new primary admin within 30 days. I'll guide you through the steps:

1. Check the invite received from the email.
2. From the email invite, select Accept Invite and sign in using your Intuit account email or user ID. 
3. Select a method to verify your identity and enter the 6-digit code provided.
4. Select Continue.

Once done, the new primary admin will now have access, and its role is now active.

If you have additional QuickBooks-related concerns, you can always reply back to this thread. We're here, willing to assist. Take care!